1. Field of Invention
The present invention relates to an active device array substrate. More particularly, the present invention relates to an active device array substrate having an electrostatic discharge (ESD) protection function.
2. Description of Related Art
In the fabrication of liquid crystal displays, operators, machines, or testing instruments are prone to carry static electricity. When the above charge-carrying entities (operators, machines, or testing instruments) contact a liquid crystal display panel, the devices and circuits inside the liquid crystal display panel may be damaged by ESD. Therefore, ESD protection circuits are usually designed in the peripheral circuit region of the liquid crystal display panel. As for active matrix liquid crystal display panels, the ESD protection circuits are generally formed on the substrate during the fabrication of the active device array, and the active device arrays are electrically connected to the ESD protection circuits. As such, when the liquid crystal display panel is impacted by ESD, the ESD protection circuits can dissipate or alleviate the static electricity, so as to prevent the static electricity from directly impacting the devices and circuits inside the display region.
FIG. 1 is a schematic view of a conventional active device array substrate. Referring to FIG. 1, an active device array substrate 110 has a display region A and a peripheral circuit region B. The active device array substrate 110 mainly comprises a substrate 112, a plurality of scan lines 114, a plurality of data lines 116, a plurality of pixel units 118, a lead line 120, a plurality of ESD protection devices 122, and a plurality of pads 124. The scan lines 114 and data lines 116 are disposed on the substrate 112, and the pixel units 118 are disposed in the display region A. In particular, the scan lines 114 and data lines 116 are electrically connected to the pixel units 118, and voltage signals can be transmitted to the pixel units 118 through the scan lines 114 and data lines 116. In addition, the scan lines 114 and the data lines 116 are electrically connected to the corresponding pads 124 respectively.
As shown in FIG. 1, the lead line 120 is disposed in the peripheral circuit region B, and electrically connected to one end of the respective ESD protection devices 122. The other end of the respective ESD protection devices 122 is electrically connected to the corresponding scan lines 114 and data lines 116. In particular, when the ESD phenomenon occurs on the substrate 112, the electrostatic charges are dispersed through the lead line 120, thus avoiding the accumulation of electrostatic charges. In another aspect, the ESD protection device 122 consumes the energy of the electrostatic charges to alleviate the ESD impact.
It should be noted that, the lead line 120 crosses the scan lines 114 and the data lines 116. When the ESD phenomenon occurs at the pads 124, the static electricity can directly pass through a cross line position C, which may easily induce the electrostatic discharging at the cross line position C, thus causing short of the lead line 120 and the scan lines 114 (data lines 116). As a result, the production yield is reduced and the manufacturing cost is increased, so it is necessary to improve the conventional art.